The spray painting of automobile bodies, engines and a variety of industrial and consumer articles is carried out in specialized enclosures called paint spray booths. These booths provide a controlled work area for the painting operations that enhances worker safety and minimizes the amount of contaminants that adversely impact a finished paint job. Booths can vary significantly in size and design. The booths have a work area where the actual painting is done and a backsection/underbooth area where paint overspray is removed from the air. In small or low production systems, this is accomplished by pulling the paint laden air through a series of disposable filters. More commonly, a moving stream of air generated by booth exhaust fans pulls the paint overspray through a curtain or spray of recirculating water effectively scrubbing the paint particles from the air into a water or aqueous phase for recovery or processing. The water and scrubbed paint particles are carried to a sump basin where the paint particles are separated from the water so that the water can be recycled, and the safe deposal of waste paint solids.
Paint is a highly adhesive film forming material. It tends to readily adhere to any exposed surface, including the interior of the spray booth where it can build up and eventually reduce air and water flow, block drains, damage pumps and plug screens. This reduces booth efficiency and significantly increases operating costs. For this reason, chemical “detackifiers” are usually added to the recirculating water. These detackifiers improve the scrubbing efficiency of the booth, prevent the paint from adhering to booth surfaces, and aid in the collection and removal of paint solids from the recirculating water stream.
Conventionally, solvent-based or solvent borne paints were most commonly employed in spray booths. More recently, increased environmental awareness has resulted in regulations limiting the amount of volatile organic compounds (VOCs) that can be released. This has resulted in an increased use of waterborne paints and reformulation of existing solvent based ones to reduce VOCs. These materials, while not as tacky as solvent based materials, are much more difficult to separate from water and due to their surfactant load are much more prone towards generating significant amounts of foam and require different treatments than their solvent based analogs. Consequently, a need has developed for detackifiers that cannot only reduce the stickiness of traditional paints but also deal with the need to control foam and improve collection of newer, reformulated water based and hazardous air pollutant (HAP) compatible solvent based paints (ones determined not to contain any materials regulated as HAPs).
Current economic concerns and environmental awareness have also dictated that these products be cost effective and perform in a sustainable manner. Moreover, due to long term corrosion concerns, several manufacturers have begun placing restrictions on the amount of chlorides that a product can contain or the amount of chloride that can be present in the paint sludge systems. As a result, there is an increasing need to provide detackifiers that do not result in chloride accumulation in the environment to meet these environmental sustainability goals.